Effect of High Pressure Heat Treatment on the Phase Transformation Dynamics of α+γ₂→ß in Cu-Al Alloy

Abstract

In this paper, high pressure heat treatment for Cu-Al alloy is carried out at the pressure of 5GPa and the heating temperature of 700°C for 15 minutes. The phase transformation temperature and time of α+γ₂→ß in Cu-Al alloy are measured before and after 5GPa pressure treatment with the help of differential scanning calorimeter (DSC). The activation energy and Avrami exponent for phase transformation are also calculated. Based on the measurement, calculation and observation of the alloy’s microstructure, the effect of 5GPa pressure treatment on the phase transformation of α+γ₂→ß in Cu-Al alloy is discussed thoroughly. The results show that 5GPa pressure treatment can decrease the phase transformation temperature and activation energy of α+γ₂→ß in the alloy. It can also shorten the phase transformation time while increasing the Avrami exponent. These are beneficial to the phase transformation of α+γ₂→ß in Cu-Al alloy since the microstructure of Cu-Al alloy gets refined and dislocation density increases after the high pressure heat treatment. Note that the high pressure process has less effect on the mechanism of phase transformation.

Keywords:
Cu-Al alloy; 5GPa pressure treatment; solid state transformation of α+γ₂→ß; microstructure